1.) Hold down the Ctrl and Shift keys together
2.) Right click on the ZA icon near your clock in the system tray lower right corner
3.) Choose 'Reset' from the box that comes up
4.) Choose Yes on the Reset Settings dialog box
5.) When prompted, choose OK to restart your system
6.) Follow the on screen configuration prompts after reboot

for c) try to boot the system selectively to find out any conflicting software:

1.) Click Start -> Run
2.) Type MSConfig in the run box and click OK
3.) Once in MSConfig, click the Startup Tab
4.) Remove the checks from everything except ZLClient
5.) Click the Services Tab
6.) Place a check in "Hide All Microsoft Services"
7.) Now remove checks from everything other than TrueVector Internet
Monitor and ForceField (if present), and click OK.
8.) Restart your computer

NOTE: You can place your computer back into a normal startup process by
going back into msconfig and choosing the Normal Startup option on the
General tab.

Please note also that ZA does not play nice with many other security tools. They may block its correct functioning including updates. For example, spyware doctor, spysweeper, trojan hunter, win patrol, PCtools Threat Fire, Mcafee, Norton, Symantec, Adaware, SpybotS&D, WinPatrol, AVG, Avast free, NOD, Kaspersky, Comodo, Rising, PC Doctor, MS Security essential, Avira and many others. If you want to troubleshoot issues with ZA please remove these tools (not enough to disable) and install back (if you really need) only after you see your ZA is working as it should. Double check you have really removed all other security tools by running this utility: http://www.appremover.com/